A
In the United States，30 percent of the adult population has a “weight problem”．To many people，the cause is clear: we eat too much.But scientific evidence does little to support this idea.Going back to the America of 1910，we find that people were thinner than today，yet they ate more food.In those days people worked harder physically，walked more，used machines much less，and didn't watch television.
Several modern studies，moreover，have shown that fatter people don't eat more on average than thinner people.In fact，some investigations(调查)，such as a 1970 study of 3，545 London office workers，report that，on balance，fat people eat less than slimmer people.
Studies show that slim people are more active than fat people.A study by a research group at Stanford University School of Medicine found the following interesting facts.The more the men ran，the greater loss of body fat.The more they ran，the greater their increase in food intake(吸收)．Thus those who ran the most ate the most，yet lost greatest amount of body fat.
【语篇解读】 很多人认为肥胖是由吃得多引起的，但为什么有些人虽然吃得多但仍然苗条呢？让本文作者告诉你答案吧。
1．Based on the statistics given in the article，suppose there are 500 adult Americans，about how many of them will have weight problems?
A．30. B．50.
C．100. D．150.
D [数字计算题。由第一段第一句提到的比例可知，有500×30% ＝150人。]
2．In comparison with the adult American population today，the Americans of 1910 ________．
A．ate more food and had more physical activities
B．ate less food but had more activities
C．ate less food and had less physical exercises
D．had more weight problems
A [细节理解题。由第一段第四、五句可知，那时人们吃得多但是仍然苗条的原因是干体力活多，走的路多。]
3．What has modern medical and scientific research reported to us?
A．Fat people eat less food and are less active.
B．Fat people eat more food than thin people and are more active.
C．Fat people eat more food than thin people but are less active.
D．Thin people run less，and need less food to eat.
A [细节理解题。由第二段最后“on balance，fat people eat less than slimmer people”和第三段开头“Studies show that slim people are more active than fat people.”可知答案为A。]
